Aduev, a UDC 535.36:620.3 and M. V. Ananyeva bCoeffi cients of transmission, absorption, and refl ectance of a composite based on pentaerythritol tetranitrate and spherical cobalt nanoparticles were calculated as functions of sample thickness and mass fraction of metal particles using Mie theory and radiative transfer theory (spherical harmonics method). It was shown that the coeffi cient of refl ectance of light normally incident on the half-space with the plane boundary increased as the Co-particle radius increased. This was because of increases of both the single-scattering albedo and the modulus of the scattering anisotropy factor. The developed method for calculating optical properties of composites based on a transparent matrix with metal nanoparticle inclusions could be used to process experimental light-scattering spectroscopy data.Introduction. The development of light-scattering spectroscopic methods is a high-priority problem because a large number of natural and industrial objects, the rapid and non-destructive monitoring of which is required for technical applications, can both scatter and absorb light. Several studies focused on the solution of this problem [1][2][3][4][5]. A method for obtaining diffuse-refl ectance and transmission spectra was developed and applied to the study of gastric mucous membranes [1]. A method for obtaining diffuse-refl ectance spectra of biological samples using an integrating sphere was proposed [2]. The researchers showed that the developed spectrometer could be used to investigate human skin samples. The use of scattering spectroscopic methods for blood analysis was examined [3,4]. Thus, a rapid blood-analysis method with determination of the concentrations of hemoglobin and its derivatives that did not require pretreatment, including centrifugation, was proposed [3]. The method was based on obtaining diffuse-transmission spectra and their approximation using a Monte-Carlo method and several approximations describing blood spectral properties as a function of composition. These ideas were further developed [4] by proposing and validating a non-invasive blood-analysis method based on obtaining the diffuse-refl ectance spectrum of lip mucous membrane using a fi ber-optic detector. A method for interpreting multi-spectral images of biological tissues that could produce the spatial distribution of their biophysical parameters was proposed [5].Theoretical methods for processing results are insuffi ciently developed and limit the use of a photometric sphere and other procedures for studying light-scattering systems. The principal theories such as dual-beam and diffusion approximations invoke several assumptions that muddle the results and make them more qualitative than quantitative. The Monte-Carlo method often requires long computations to reach the required accuracy. Therefore, theoretical methods for processing experimental results, including the use of radiative transfer theory, are needed in order to utilize as much as possible the advantages of optical measurements w...

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The absorption and scattering efficiency factors for cobalt nanoparticles over wavelengths ranging from 400 -1200 nm were calculated. The maximum values and corresponding radii of the absorption efficiency were shown to be dependent upon the incident light wavelength. The highest scattering factor values in the studied spectral range were between 2.2 and 2.4. If the absorptivity of the matrix increases, absorption of the light by cobalt nanoparticles begins to dominate over scattering process. The obtained results allow us to predict the optical properties for composite materials based on a transparent matrix with cobalt nanoparticles, which is essential for the accurate modeling of such systems' behavior under laser irradiation.

In this work simulation of the kinetics of the explosive decomposition process in silver azide

In this work, the modes of synthesizing copper nanoparticles for use in an optical initiation system were proposed. The optimal sizes of the copper particles in the pentaerythritol tetranitrate were estimated, for use as a cup of the optical detonator on the first and the second harmonics of the Nd:Yag laser. For the first harmonic of the Nd:Yag, laser the absorptivity maximum was 0.097 and the particle's radius was 98 nm, for the second harmonic, the absorptivity maximum rose more than in 34 times, and it was equal to 3.29 and the copper particle's radius was 30 nm. Comparison of the calculated critical energy densities shows that pentaerythritol tetranitrate, which contains the copper nanoparticles, must be significantly more sensitive (∼29 times) to the second harmonic than to the first. The modes of synthesis for copper nanoparticles of the required size were determined and tested.